I just finished up doing the blower motor on the 240 and am pleased to say it went without a hitch... until I started the car up and the SRS light is now permanently illuminated.

I remember unhooking the orange airbag connection at some point during the blower motor repair, but I hooked it back up during re-assembly. It's possible I may have reconnected the battery while the airbag was unplugged, hence the light coming on. Anyway... the light is now on and the normal code checking/reset procedure with the wire behind the SRS plug is not working.

When I ground the test wire to the cigarette lighter, the SRS light turns off as it should. However, holding it in place for 3+ seconds yields no codes. The SRS light simply re-illuminates without flashing. Similarly, grounding 3 times quickly doesn't reset the light. I've tried checking and clearing codes dozens of times now and have gotten nothing. There are no other electrical oddities present as if I had botched a ground wire somewhere.

The SRS Green book indicates that the behavior I described is either an open circuit between the airbag and the crash sensor, or an internal fault with the crash sensor.

I tested the circuit between the airbag and crash sensor and got a reading of 200 ohms back, which is exactly what it should be, so it appears there are no wiring faults. I also replaced the crash sensor, capacitor box, and the wiring harness up to the center console with no change in behavior.

I'm not sure where to look next. Any thoughts?